Introduction of Permissible Temperature Range of Medium in Selection of Pneumatic Butterfly Valve

The main control parameters of pneumatic butterfly valve are nominal diameter, nominal design pressure, allowable temperature range of medium, flow coefficient, etc. Special control valves should be selected for strict situations where the flow rate is proportional to the opening height. Ball valves and butterfly valves can be selected when they are roughly adjusted.
The sealing performance of pneumatic butterfly valve is one of the main indexes to evaluate the quality of valve. The sealing performance of pneumatic butterfly valve mainly includes two aspects: internal leakage and external leakage. Internal leakage refers to the degree of sealing of the medium between the seat and the closure.

Leakage refers to the leakage of filling part of pneumatic butterfly valve stem, the leakage of middle gasket part and the leakage of valve body caused by casting defects. Leaks are not allowed to occur. The ideal flow characteristics of pneumatic butterfly valve include fast opening, parabola, linearity and equal percentage. Pneumatic butterfly valve with suitable flow characteristics should be selected according to the actual flow characteristics.